An Intimate Guide
To the Solar System

In the 1870s, Giovanni Schiaparelli produced a map of Mars that quickly became this planet's standard way of looking at that one. Part of its appeal lay in the undoubted precision of his observations; another part was the allusive system of place-names he introduced. The observations have since been superseded, eventually by space missions. The names remain the basis of Martian geography to this day.

Schiaparelli turned the dim mottled sphere into a mosaic of references to classical geography and mythology that still has the power to entrance: Elysium, Mare Sirenum (the sea of sirens), Hellas, Margaritifer Sinus (the bay of pearls), Argyre and Chryse (the silver and golden lands of Burma and Thailand), Solis Lacus (the lake of the sun) and so on. Percival Lowell, a rich Bostoner then falling under the Martian spell, praised the euphonious nomenclature as an "at once appropriate and beautiful scheme, in which Clio [the muse of history] does ancillary duty to Urania [the muse of astronomy]."

It's a phrase that one imagines Dava Sobel would take some pleasure in, not least because similar ancillary duties from one muse to another provide much of the delight in "The Planets." This impressively succinct tour of the solar system not only tells the reader what is known about the Earth's setting and siblings but also sketches the different ways in which humans can relate to the lights that wander through our skies. It touches on aesthetics, mythology, folklore, science fiction and even, God help us, astrology -- not to mention astronomy and its recent and more dramatic adjunct, robotic exploration.

'Fantastic Aberrations'

Ms. Sobel's own primal relationship with the planets, she tells us, was that of a collector. Seized as a child by the planets' "fantastic aberrations" -- days as long as years, years that last centuries, temperatures that can freeze air or melt lead -- she set about filling a shoebox with facsimiles in the form of painted marbles, Ping-Pong balls and the like. "The Planets" is intended as a literary expression of that childish cabinet of curiosities, a way of showing off the variety of a small set of disparate wonders whose true scale is beyond us.

In the time between Ms. Sobel's childish enthusiasm and her mature reflection, the study of the planets has changed beyond recognition. New astronomical techniques have allowed us more precise views from a distance, and we have managed to get up close, too. Visiting the planets has heightened our sense of their "personalities." In the outer solar system the "ice giants," Uranus and Neptune, are far more distinct in our imaginations today than they were before the space age. Thanks to brief visits by a single spacecraft -- Voyager 2 -- we have seen Uranus in its pale turquoise, spinning sideways through the sky set in ghostly rings, and Neptune in deep marine blue, escorted by a wondrous strange world-size moon studded with geysers of nitrogen.

The exploration of the solar system has also drawn out new ways in which the Earth's siblings fall into groups. Recent studies of Mars have shown that its surface chemistry has been deeply affected by sulfur in ways that suggest a passing similarity to Io, Jupiter's sulfurous and spectacularly volcanic moon. Possible similarities between Mars and Earth are being pushed back to the earliest days of their youth. And Pluto, once seen as an oddball, all on its own at the system's edge, has in the past few years been revealed as just one of a growing swarm of icy dwarf planets with orbits reaching far out toward the depths of interstellar space.

Pluto's new-found friends raise again the question of how many planets there are. Ms. Sobel limits herself to the usual suspects, in nine chapters, though she forces Uranus and Neptune to share one in order to give the Earth's moon one of its own. To avoid the rhythmic tiresomeness that the another-chapter-another-planet template might be prey to, she approaches each in a fresh way, twice going so far as to enlist surrogate narrators.

Thus the chapter on Uranus and Neptune is told in the form of a fictional letter from Caroline Herschel, the first woman to discover a new heavenly body, to Maria Mitchell, the first American woman to do so. The chapter on Mars is, more unusually, narrated by ALH 84001, sometimes known as "Big Al," the Martian meteorite that was the center of a furor in the mid-1990s, when scientists tentatively identified possible signs of life within it.

Irksome Conceit

For the chapters told in her proper persona, Ms. Sobel matches an ancillary theme to each celestial body. Venus brings out the poetry, the moon the folklore and Jupiter the disquisition on astrology that is the most irksome of the book's conceits. Astrology has obviously played an important role in human traffic with the planets -- that the planets do things repeatedly over periods of decades and centuries makes them beacons of predictability in this chaotic sublunary sphere. But that role is described here without setting it either in its historical context as a crucial component of early astronomy or in its contemporary context as a somewhat troubling form of sanctioned superstition.

And while I'm carping about the irrational, I should mention the grating effect of one suggestion of Ms. Sobel's -- that the transitory quirk of geometry allowing the moon to block out the sun's disk so precisely during a total eclipse might be evidence of "divine design." Such claptrap is doing enough harm in biology without being imported into astronomy. But it will doubtless add to the appeal of "The Planets" for some readers, and something for everyone is part of the point of Ms. Sobel's box of chocolates.

The various chocolates are so skillfully confected that the reader barely notices their substantial freight of science: The liqueurs in the soft centers have a genuine kick. The light, evocative prose -- Jupiter's face is "an expanse of pure weather," Martian explorers find themselves "half hoping, half fearing that they are trespassing" -- conveys a lot of normally much harder-won knowledge. If there is a lack in the book, it's not in the explanations of current knowledge but in the author's unwillingness to put what we know now into the context of what is to come. You would hardly guess, to read this book, how much excitement there is at present about the discovery and study of planets, including earthlike ones, around other stars. Nor would you get much of a feeling of the wisdom or otherwise of giving NASA a hundred billion dollars to return humans to the moon.

Like many presentation boxes, "The Planets" seems likely often to be bought as a gift for others; perhaps it could be thought of as a selection of shiny tree ornaments as much as a box of wonders or chocolates, and it may well have been conceived with that seasonal similarity in mind. If so it is a testament to Ms. Sobel's acumen that a wide range of readers will enjoy being given it. It is a testament to her clear joy in communicating what moves her that for many of them it will read like a gift from the author herself.

Mr. Morton is the author of "Mapping Mars: Science, Imagination, and the Birth of a World."